Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention comprises first to third lens groups arranged along an optical axis, wherein the first lens group has positive (+) refractive power, the second lens group has positive (+) refractive power, the third lens group has negative (-) refractive power, the first lens group includes a prismatic lens, the first lens group and the second lens group are fixed groups, and the third lens group is a movable group.

Description

Optical system and camera module

[0001] The present invention relates to an optical system for enhanced optical performance and a camera module including the same.

[0002] Camera modules perform the function of capturing objects and saving them as images or videos, and are installed in various applications. In particular, camera modules are manufactured in ultra-compact sizes and are applied not only to portable devices such as smartphones, tablet PCs, and laptops, but also to drones and vehicles, providing a wide range of functions.

[0003] For example, the optical system of a camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. In this case, the camera module can perform an autofocus (AF) function that aligns the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zooming function of zooming up or zooming out by increasing or decreasing the magnification of a distant object through a zoom lens. Additionally, the camera module employs image stabilization (IS) technology to correct or prevent image shaking caused by camera movement resulting from unstable fixed devices or user movements.

[0004] The most important element for such camera modules to obtain an image is the imaging lens that forms the image. Recently, there has been growing interest in high performance, such as high image quality and high resolution, and research is being conducted on optical systems containing multiple lenses to achieve this.

[0005] For example, research is being conducted using multiple imaging lenses with positive (+) or negative (-) refractive power to implement a high-performance optical system. An optical system containing multiple lenses may have a set Effective Focal Length (EFL). In this case, when the value of the Effective Focal Length (EFL) is relatively large, the lens adjacent to the object side has a large aperture or the largest aperture among the multiple lenses. Consequently, since the lens closest to the object side has a relatively large size, there is a problem in that it is difficult to miniaturize the optical system.

[0006] An optical system containing multiple lenses may have a relatively large height. For example, as the number of lenses increases, the distance from the image sensor to the object surface of the lens adjacent to the object may increase. Accordingly, the overall thickness of a device such as a mobile device like a smartphone in which the optical system is placed may increase, and there is a problem that it is difficult to miniaturize.

[0007] Camera modules for close-range imaging have a shorter TTL compared to conventional camera modules. As another example, camera modules for long-range imaging have a longer TTL compared to conventional camera modules. However, since portable terminals have limited installation space for camera modules, it is difficult to mount camera modules for long-range imaging or camera modules capable of adjusting image magnification (zoom camera modules). Therefore, a new optical system capable of solving the aforementioned problems is required.

[0008] The present embodiment aims to provide an optical system and a camera module with improved optical characteristics.

[0009] In addition, it is possible to provide an optical system that can be implemented in a small and compact manner.

[0010] Additionally, an optical system can be provided in which the lengths of the first direction and the second direction of at least one lens among the plurality of lenses that is adjacent to the object side or adjacent to the outside of the terminal are different. That is, an optical system can be provided in which at least one or two or more of the lenses have different lengths in two mutually orthogonal axis directions.

[0011] In addition, we aim to provide an optical system applicable to a folded camera or macro mode having a thin thickness or height.

[0012] To solve the above technical problem, an optical system according to an embodiment of the present invention includes first to third lens groups arranged along an optical axis, wherein the first lens group has a positive (+) refractive power, the second lens group has a positive (+) refractive power, the third lens group has a negative (-) refractive power, the first lens group includes a prism lens, the first lens group and the second lens group are fixed groups, and the third lens group is a moving group.

[0013] The first lens group above may include a single power prism lens having an object side that is convex and a sensor side that is concave.

[0014] The first lens group includes a first lens, a second lens which is a prism lens, and a third lens, and the first to third lenses are bonded lenses, the second lens group includes a fourth lens, a fifth lens, and a sixth lens, and the third lens group may include a seventh lens and an eighth lens.

[0015] The first lens above may have a positive (+) refractive power, and the third lens may have a negative (-) refractive power.

[0016] The above-mentioned fourth lens may have a positive (+) refractive power, the above-mentioned fifth lens may have a positive (+) refractive power, and the above-mentioned sixth lens may have a negative (-) refractive power.

[0017] The above seventh lens may have a negative (-) refractive power, and the above eighth lens may have a positive (+) refractive power.

[0018] The above-mentioned fourth lens and fifth lens may have a meniscus shape in which the side of the object is convex.

[0019] The above-mentioned sixth lens may have a meniscus shape with a convex side of the object, and the above-mentioned seventh lens may have a meniscus shape with a concave side of the object.

[0020] An aperture may be placed between the above-mentioned sixth lens and the above-mentioned seventh lens.

[0021] The following condition can be satisfied. <Condition> 1 < TD_LG2 / TD_LG3 < 2 (In the above condition, TD_LG2 is the length of the second lens group in the optical axis direction, and TD_LG3 is the length of the third lens group in the optical axis direction.)

[0022] To solve the above technical problem, an optical system according to another embodiment of the present invention includes first to eight lenses arranged along an optical axis, wherein the second lens is a prism lens, the first lens has a positive (+) refractive power, the third lens has a negative (-) refractive power, the fourth lens has a positive (+) refractive power, the fifth lens has a positive (+) refractive power, the sixth lens has a negative (-) refractive power, the seventh lens has a negative (-) refractive power, and the eighth lens has a positive (+) refractive power.

[0023] The first to third lenses may be a first lens group having positive (+) refractive power, the fourth to sixth lenses may be a second lens group having positive (+) refractive power, and the seventh and eighth lenses may be a third lens group having negative (-) refractive power.

[0024] The first lens group and the second lens group are fixed groups, and the third lens group may be a moving group.

[0025] The above-mentioned fourth lens and fifth lens may have a meniscus shape in which the side of the object is convex.

[0026] The following condition can be satisfied. <Condition> 0.35 < |L1R1| / |L3R2| < 1 (In the above condition, L1R1 is the radius of curvature of the object side of the first lens, and L3R2 is the radius of curvature of the sensor side of the third lens.)

[0027] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 5 (In the above condition, TTL is the optical axis distance from the vertex of the object side of the first lens to the top plane of the image sensor, and ImgH is the maximum diagonal length of the image sensor.)

[0028] The optical system and camera module according to the present embodiment have various magnifications and can have excellent optical characteristics when providing various magnifications. Specifically, the embodiment can have various magnifications and provide an autofocus (AF) function for the subject by controlling a set number of lenses, a lens group having refractive power, a plurality of lenses having a set shape and focal length, and a moving distance of a moving lens group.

[0029] In addition, each of the multiple lens groups can correct aberration characteristics or mutually complement aberration characteristics that change due to movement. Accordingly, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when the magnification changes.

[0030] In addition, the effective focal length (EFL) can be controlled by moving only some of the lens groups among multiple lens groups, and the moving distance of the moving lens groups can be minimized. Accordingly, the embodiment can significantly reduce the moving distance of the lens groups when changing the magnification and minimize the power consumption required when moving the lens groups.

[0031] In addition, the optical system according to the present embodiment has enhanced optical characteristics and can have a large BFL (Back focal length), thereby providing an optical system suitable for a folded camera module.

[0032] FIG. 1 is a diagram showing the configuration of an optical system according to the present embodiment operating in a first mode.

[0033] FIG. 2 is a configuration diagram of an optical system according to the present embodiment operating in a second mode.

[0034] FIG. 3 is a table showing the aspherical coefficients of lenses in an optical system according to the present embodiment.

[0035] FIG. 4 is a graph showing data on the aberration characteristics of the optical system according to the present embodiment operating in the first mode.

[0036] FIG. 5 is a drawing for explaining the D-cut lens of the present invention.

[0037] FIG. 6 is an example of a portable terminal having an optical system according to the present embodiment.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0039] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0040] In addition, terms used in this embodiment (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which this embodiment belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0041] Furthermore, the terms used in this embodiment are for the purpose of describing the embodiment and are not intended to limit the invention.

[0042] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0043] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present embodiment. These terms are used merely to distinguish the components from other components and are not intended to limit the essence, order, or sequence of the components.

[0044] And, where it is stated that a component is 'connected', 'combined', or 'connected' to another component, this may include not only cases where the component is directly 'connected', 'combined', or 'connected' to the other component, but also cases where it is 'connected', 'combined', or 'connected' due to another component located between the component and the other component.

[0045] Furthermore, when described as being formed or placed "above" or "below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above" or "below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0046] In the description of the invention, "object side" may refer to a surface of the lens facing the object side with respect to the optical axis (OA), and "sensor side" may refer to a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. "Object side" may be the "object side," and "sensor side" may be the "image side." One surface of the lens being convex may refer to a convex shape in the optical axis or paraxial region, and one surface of the lens being concave may refer to a concave shape in the optical axis or paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses listed in the lens data table may refer to values ​​(unit, mm) in the optical axis. The vertical direction may refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface may refer to the end of the effective area of ​​the lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above paraxial region refers to a very narrow region near the optical axis, and is a region where the distance of light rays from the optical axis (OA) is almost zero. Hereinafter, the term optical axis may include the center of each lens or a very narrow region near the optical axis.

[0047] The optical axis (OA) may refer to the central axis on the path of light where light incident from the second direction (Y-axis direction) by the prism lens (102) bends into the first direction (X-axis direction).

[0048]

[0049] The optical system (1000) according to the present embodiment may include a plurality of lens groups. Specifically, the optical system (1000) may include a plurality of lens groups, each including at least one lens. For example, the optical system (1000) may include a first lens group (LG1), a second lens group (LG2), a third lens group (LG3), and an image sensor (300) that are sequentially arranged from the object side toward the image sensor.

[0050] The first to third lens groups (LG1, LG2, LG3) may each have a positive (+) or negative (-) refractive power. The first lens group (LG1) and the second lens group (LG2) may have refractive powers of the same sign. For example, the first lens group (LG1) may have a positive (+) refractive power, and the second lens group (LG2) may have a positive (+) refractive power. Additionally, the third lens group (LG3) may have a negative (-) refractive power.

[0051] At least one of the first lens group (LG1), the second lens group (LG2), and the third lens group (LG3) may be provided to be movable in the direction of the optical axis (OA). For example, the third lens group (LG3) may be provided to be movable, while the first lens group (LG1) and the second lens group (LG2) may be fixed. The first lens group (LG1) and the second lens group (LG2) may be placed in fixed positions, and the third lens group (LG3) may be provided to be movable in the direction of the optical axis (OA).

[0052] The first lens group (LG1) may include a plurality of lenses. Specifically, the first lens group (LG1) may include one or more lenses having opposite refractive powers. For example, the first lens group (LG1) may include three lenses.

[0053] The first lens group (LG1) may include a prism lens. The optical system (1000) may reduce the first direction (X-axis direction) and the second direction (Y-axis direction) of the optical system (1000) by including a second lens (102) which is a prism lens. If the optical system (1000) does not include a prism lens, a plurality of lenses within the optical device including the optical system (1000) may be arranged to extend in a direction perpendicular to the surface of the optical device.

[0054] Accordingly, multiple lenses have a high height in a direction perpendicular to the surface of the optical device, and it may be difficult to form the thickness of the optical device into an ultra-thin shape. A prism lens can change light incident perpendicular to the plane of the optical device into a direction parallel to the surface of the optical device. That is, multiple lenses included in the optical system (1000) can be arranged to extend in a direction parallel to the surface of the optical device, and the optical device can be formed with a thin thickness.

[0055] A driving member (not shown) may be connected to a prism lens. The driving member may include at least one actuator. For example, the driving member may include at least one of a VCM (Voice Coil Motor), a piezo-electric device, a shape memory alloy, or a MEMS device as the actuator. The driving member can move the prism lens using the driving force of the actuator. For example, the driving member can tilt the prism lens along a first axis (X-axis) or a second axis (Y-axis). Accordingly, the camera module (1520) can correct shaking.

[0056] It includes a detection unit (not shown) for detecting shaking of the camera module (1520), and the detection unit can detect rotation and position changes applied to the camera module (1520). The detection unit may include at least one of a sensor that detects changes in angular velocity, for example, a gyro sensor, and an acceleration sensor that detects changes in acceleration.

[0057] The camera module (1520) can control the movement of the prism lens by a control signal. Specifically, if shaking occurs in the camera module (1520), information about the shaking, such as the degree of rotation and position change of the sensors, can be detected, and correction for the shaking can be performed.

[0058] Accordingly, the camera module (1520) according to the embodiment can effectively correct shaking caused by rotation and shaking caused by changes in position when photographing a subject located at infinity or macro distance. Therefore, the camera module (1520) can have improved optical characteristics.

[0059]

[0060] A plurality of lenses included in the first lens group (LG1) can be formed into a single lens. A plurality of lenses included in the first lens group (LG1) can be formed into a bonded lens. The surfaces facing each other among the plurality of lenses included in the first lens group (LG1) can be bonded together.

[0061] According to a variation, a plurality of lenses included in the first lens group (LG1) may have a set spacing. Specifically, the spacing between the plurality of lenses included in the first lens group (LG1) may remain constant and not change in the operation mode described later. For example, the spacing between the first lens (101) and the second lens (102), and the spacing between the second lens (102) and the third lens (103), may remain constant and not change according to the operation mode described later.

[0062] The second lens group (LG2) may include multiple lenses. Specifically, the second lens group (LG2) may include three or more lenses having opposite refractive powers. The number of lenses included in the second lens group (LG2) may be equal to the number of lenses included in the first lens group (LG1). For example, the second lens group (LG2) may include three lenses.

[0063] A plurality of lenses included in the second lens group (LG2) may have a set spacing. Specifically, the spacing between the plurality of lenses included in the second lens group (LG2) may remain constant and not change in the operation mode described later. For example, the spacing between the fourth lens (104) and the fifth lens (105), and the spacing between the fifth lens (105) and the sixth lens (106) may remain constant and not change according to the operation mode described later.

[0064] The third lens group (LG3) may include multiple lenses. Specifically, the third lens group (LG3) may include two or more lenses having opposite refractive powers. The number of lenses included in the third lens group (LG3) may be smaller than the number of lenses included in the second lens group (LG2). For example, the third lens group (LG3) may include two lenses.

[0065] Multiple lenses included in the third lens group (LG3) may have a set spacing. Specifically, the spacing between multiple lenses included in the third lens group (LG3) may remain constant and not change in the operation mode described later. For example, the spacing between the seventh lens (107) and the eighth lens (108) may remain constant and not change according to the operation mode described later.

[0066]

[0067] The optical system (1000) may include a plurality of lens groups (LG1, LG2, LG3) and an image sensor (300) arranged sequentially from the object side toward the sensor. Additionally, the optical system (1000) may include a plurality of lenses included in the lens groups (LG1, LG2, LG3), for example, a first lens (101), a second lens (102), a third lens (103), a fourth lens (104), a fifth lens (105), a sixth lens (106), a seventh lens (107), and an eighth lens (108).

[0068] The first lens group (LG1) may include a first lens (101), a second lens (102), and a third lens (103). The second lens group (LG2) may include fourth to sixth lenses (104 to 106). The third lens group (LG3) may include seventh to eighth lenses (107 to 108). The first to eighth lenses (101 to 108) and the image sensor (300) may be arranged sequentially along the optical axis (OA) of the optical system (1000).

[0069] Each of the plurality of lenses (100) may include an effective region and a non-effective region. The effective region may be a region through which light incident on each of the first to eighth lenses (101 to 108) passes. That is, the effective region may be a region where the incident light is refracted to realize optical characteristics.

[0070] The non-effective region may be positioned around the perimeter of the effective region. The non-effective region may be an area where light is not incident. In other words, the non-effective region may be an area unrelated to optical properties. Additionally, the non-effective region may be an area fixed to a barrel (not shown) that accommodates the lens.

[0071] Referring to FIG. 5, at least one of the first to eighth lenses (101 to 108) in the optical system (1000) according to the present embodiment may have a D-cut technique applied. When the D-cut technique is applied, the height of the entire optical system may be reduced by cutting off a portion of the lens effective diameter or rib. Here, the height of the entire optical system may refer to the length in a direction perpendicular to the optical axis, rather than the TTL. The D-cut lens may have a non-circular shape, and the length (A) in the first direction (X-axis direction) and the length (B) in the second direction (Y-axis direction) may be different.

[0072]

[0073] The image sensor (300) can detect light. The image sensor (300) can detect light that has passed through a plurality of lenses, for example, the first to eighth lenses (101 to 108) in sequence. The image sensor (300) may include a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS), etc.

[0074] The optical system (1000) may further include a filter (400). The filter (400) may be placed between a plurality of lenses and an image sensor (300). The filter (400) may be placed between the image sensor (300) and the third lens group (LG3) that is closest to the image sensor (300) among a plurality of lens groups (LG1, LG2, LG3). For example, the filter (400) may be placed between the image sensor (300) and the eighth lens (108), which is the last lens of the third lens group (LG3) that is closest to the image sensor (300) among the plurality of lenses.

[0075] The filter (400) may include at least one of an optical filter, such as an infrared filter or a cover glass. The filter (400) may pass light of a set wavelength band and filter light of a different wavelength band. If the filter (400) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (300). Additionally, the filter (400) may transmit visible light and reflect infrared light.

[0076] The optical system (1000) may include an aperture (not shown). The aperture can control the amount of light incident on the optical system (1000).

[0077] The aperture may be positioned in front of the first lens (101) or between two selected lenses among the first to eighth lenses (101 to 108). For example, the aperture may be positioned between the sixth lens (106) and the seventh lens (107). Additionally, at least one of the first to eighth lenses (101 to 108) may function as an aperture. For example, the object side or sensor side of one of the selected lenses among the first to eighth lenses (101 to 108) may function as an aperture that controls the amount of light.

[0078]

[0079] The optical system according to the present embodiment of the invention will be described.

[0080] FIG. 1 is a configuration diagram of an optical system according to the present embodiment operating in a first mode, FIG. 2 is a configuration diagram of an optical system according to the present embodiment operating in a second mode, FIG. 3 is a table showing the aspherical coefficients of lenses in an optical system according to the present embodiment, FIG. 4 is a graph showing data on the aberration characteristics of an optical system according to the present embodiment operating in a first mode, and FIG. 5 is a drawing for explaining the D-cut lens of the present invention.

[0081] Referring to FIG. 1, the optical system (1000) includes a lens portion, and the lens portion may include first to eighth lenses (101 to 108). The first to eighth lenses (101 to 108) may be arranged sequentially along the optical axis (OA) of the optical system (1000). Light corresponding to information about an object may pass through the first to eighth lenses (101 to 108) and a filter (400) and be incident on an image sensor (300).

[0082] The first lens (101) can be positioned closest to the object side. The first lens (101) can be positioned furthest from the sensor side. The first lens (101) can have a positive (+) refractive power at the optical axis (OA).

[0083] The first lens (101) may be positioned closest to the object side. The first lens (101) may be positioned furthest from the sensor side. The first lens (101) may have a positive (+) refractive power at the optical axis (OA). The first lens (101) may include plastic or glass material. For example, the first lens (101) may be provided with glass material.

[0084] With respect to the optical axis (OA), the first surface (S1) on the object side of the first lens (101) may be convex, and the second surface (S2) on the sensor side may be flat. The first lens (101) may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (101) may be provided without a critical point from the optical axis to the end of the effective area.

[0085]

[0086] The second lens (102) may be positioned second from the object side. The second lens (102) may be positioned seventh from the sensor side. The second lens (102) may be positioned between the first lens (101) and the third lens (103). The second lens (102) may include plastic or glass material. For example, the second lens (102) may be provided with glass material. The third surface (S3) on the object side and the fourth surface (S4) on the sensor side of the second lens (102) may be formed as flat surfaces.

[0087] The second lens (102) may be a prism lens. The second lens (102) may be a right-angle prism lens. The second lens (102) may be an optical path control member. The second lens (102) may change the path of light incident from the outside. The second lens (102) may include a mirror and a prism. The second lens (102) may rotate the optical path by 90°. The second lens (102) includes an incident surface (S3) into which light is incident, a reflective surface (RS3) that reflects the incident light, and an exit surface (S4) that emits the reflected light. The reflective surface (RS3) has an inclination angle of 45° and reflects the main ray of the incident light by 90°, thereby serving to reflect the incident light to the third lens (103). The second lens (102) can reflect light incident in the second direction (Y-axis direction) to change the path of the light to the first direction (Y-axis direction).

[0088]

[0089] The third lens (103) may be positioned as the third lens from the object side. The third lens (103) may be positioned as the sixth lens from the sensor side. The third lens (103) may be positioned between the second lens (102) and the fourth lens (104). The third lens (103) may have a negative (-) refractive power at the optical axis (OA). The third lens (103) may include plastic or glass materials. For example, the third lens (103) may be provided with glass material.

[0090] With respect to the optical axis, the object-side fifth surface (S5) of the third lens (103) may be flat, and the sensor-side sixth surface (S6) may be concave. The third lens (103) may be made of glass material and may have a spherical surface. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may be provided without a threshold point from the optical axis to the end of the effective area.

[0091]

[0092] The first to third lenses (101 to 103) may be power prism lenses formed by joining three lenses. The power prism lenses may be reflective members having refractive power. The power prism lenses may have positive (+) refractive power. The first to third lenses (101 to 103) may be power prism lenses formed as a single lens. When the first to third lenses (101 to 103) are formed as a single lens, the object side may be convex and the sensor side may be concave.

[0093]

[0094] The fourth lens (104) may be positioned as the fourth lens from the object side. The fourth lens (104) may be positioned as the fifth lens from the sensor side. The fourth lens (104) may be positioned between the third lens (103) and the fifth lens (105). The fourth lens (104) may have a positive (+) refractive power. The fourth lens (104) may include plastic or glass materials. For example, the fourth lens (104) may be provided with a plastic material.

[0095] With respect to the optical axis, the object-side 7th surface (S7) of the 4th lens (104) may be convex, and the sensor-side 8th surface (S8) may be concave. The 4th lens (104) may have a meniscus shape that is convex on the object side at the optical axis (OA). The 4th lens (104) may have a meniscus shape that is concave on the sensor side at the optical axis (OA). The 4th lens (104) may be made of plastic material and may have an aspherical surface. The aspherical coefficients of the 7th surface (S7) and the 8th surface (S8) may be provided as L4S1 and L4S2 of FIG. 3. At least one or both of the 7th surface (S7) and the 8th surface (S8) of the 4th lens (104) may be provided without a critical point from the optical axis to the end of the effective area.

[0096]

[0097] The fifth lens (105) may be positioned as the fifth lens from the object side. The fifth lens (105) may be positioned as the fourth lens from the sensor side. The fifth lens (105) may be positioned between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have a positive (+) refractive power. The fifth lens (105) may include plastic or glass materials. For example, the fifth lens (105) may be provided with a plastic material.

[0098] With respect to the optical axis (OA), the fifth lens (105) may have a convex ninth surface (S9) on the object side and a concave tenth surface (S10) on the sensor side. The fifth lens (105) may have a meniscus shape that is convex on the object side at the optical axis (OA). The fifth lens (105) may have a meniscus shape that is concave on the sensor side at the optical axis (OA). The fifth lens (105) is made of plastic material and may have an aspherical surface. The aspherical coefficients of the ninth surface (S9) and the tenth surface (S10) may be provided as L5S1 and L5S2 of FIG. 3. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (105) may be provided without a critical point from the optical axis to the end of the effective area.

[0099]

[0100] The sixth lens (106) may be positioned as the sixth lens from the object side. The sixth lens (106) may be positioned as the third lens from the sensor side. The sixth lens (106) may be positioned between the fifth lens (105) and the seventh lens (107). The sixth lens (106) may have a negative (-) refractive power. The sixth lens (106) may include plastic or glass materials. For example, the sixth lens (106) may be provided with a plastic material.

[0101] With respect to the optical axis (OA), the 6th lens (106) may have an object-side 11th surface (S11) that is convex and a sensor-side 12th surface (S12) that is concave. The 6th lens (106) may have a meniscus shape that is convex on the object side at the optical axis (OA). The 6th lens (106) may have a meniscus shape that is concave on the sensor side at the optical axis (OA). The 6th lens (106) is made of plastic material and may have an aspherical surface. The aspherical coefficients of the 11th surface (S11) and the 12th surface (S12) may be provided as L6S1 and L6S2 of FIG. 3. At least one or both of the 11th surface (S11) and the 12th surface (S12) of the 6th lens (106) may be provided without a critical point from the optical axis to the end of the effective area.

[0102] The aperture (STOP) can be positioned between the 6th lens (106) and the 7th lens (107). The aperture can be positioned on the sensor-side 12th surface (S12) of the 6th lens (106). The aperture can reduce TTL within the angle of view range and enable miniaturization of the optical system. Accordingly, it is possible to prevent a decrease in the yield by weight of the optical system and improve production efficiency.

[0103]

[0104] The seventh lens (107) may be positioned as the seventh lens from the object side. The seventh lens (107) may be positioned as the second lens from the sensor side. The seventh lens (107) may be positioned between the sixth lens (106) and the eighth lens (108). The seventh lens (107) may have a negative (-) refractive power. The seventh lens (107) may include plastic or glass materials. For example, the seventh lens (107) may be provided with a plastic material.

[0105] With respect to the optical axis (OA), the 7th lens (107) may have a concave 13th surface (S13) on the object side and a convex 14th surface (S14) on the sensor side. The 7th lens (107) may have a meniscus shape that is concave on the object side at the optical axis (OA). The 7th lens (107) may have a meniscus shape that is convex on the sensor side at the optical axis (OA). The 7th lens (107) is made of plastic material and may have an aspherical surface. The aspherical coefficients of the 13th surface (S13) and the 14th surface (S14) may be provided as L7S1 and L7S2 of FIG. 3.

[0106] The 13th surface (S13) of the 7th lens (107) may be provided without a critical point from the optical axis to the end of the effective area. The 14th surface (S14) of the 7th lens (107) may have a critical point from the optical axis to the end of the effective area. If the 14th surface (S14) has a critical point, it may be located in the range of 70% to 90% of the effective radius from the optical axis, preferably in the range of 80% to 85%. The critical point of the 14th surface (S14) may be located in the range of 1.0 mm to 2.5 mm from the optical axis, preferably in the range of 1.5 mm to 2.0 mm. The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where it decreases and then increases.

[0107]

[0108] The eighth lens (108) may be positioned closest to the sensor side. The eighth lens (108) may be positioned furthest from the object side. The eighth lens (108) may be positioned between the seventh lens (107) and the filter (400). The eighth lens (108) may be positioned between the seventh lens (107) and the image sensor (300). The eighth lens (108) may have a positive (+) refractive power. The eighth lens (108) may include plastic or glass material. For example, the eighth lens (108) may be provided with plastic material.

[0109] With respect to the optical axis (OA), the 8th lens (108) may have a convex 15th surface (S15) on the object side and a concave 16th surface (S16) on the sensor side. The 8th lens (108) may have a meniscus shape with the object side being convex. The 8th lens (108) may have a meniscus shape with the sensor side being concave. The 8th lens (108) is made of plastic material and may have an aspherical surface. The aspherical coefficients of the 15th surface (S15) and the 16th surface (S16) may be provided as L8S1 and L8S2 of FIG. 3.

[0110] The 15th surface (S15) of the 8th lens (108) may have a critical point from the optical axis to the end of the effective area. When the 15th surface (S15) has a critical point, it may be located in the range of 65% to 85% of the effective radius from the optical axis, preferably in the range of 70% to 80%. The critical point of the 15th surface (S15) may be located in the range of 1.0 mm to 2.0 mm from the optical axis, preferably in the range of 1.2 mm to 1.8 mm. The critical point of the 15th surface (S15) is a point where the sign of the slope value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. Additionally, the critical point of the 15th surface (S15) may be a point where the slope value of the tangent passing through the lens surface increases and then decreases, or decreases and then increases.

[0111] The 16th surface (S16) of the 8th lens (108) may have a critical point from the optical axis to the end of the effective area. When the 16th surface (S16) has a critical point, it may be located in the range of 30% to 50% of the effective radius from the optical axis, preferably in the range of 35% to 45%. The critical point of the 16th surface (S16) may be located in the range of 0.2 mm to 1.5 mm from the optical axis, preferably in the range of 0.5 mm to 1.0 mm. The critical point of the 16th surface (S16) is a point where the sign of the slope value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. Additionally, the critical point of the 16th surface (S16) may be a point where the slope value of the tangent passing through the lens surface increases and then decreases, or decreases and then increases.

[0112]

[0113] LensSurfaceRadiusThicknessndvdClearAperture1S115.8601.7701.56071.8009.690S2Infinity0.000 9.1602S3Infinity5.4001.85023.8009.160S4Infinity0.000 6.9203S5Infinity0.4001.9320.96.530S631.6600.700 6.2304S73.9801.2701.55056.3005.600S87.3400.150 5.2805S94.4701.0001.55056.3005.020S108.7200.150 4.6306S1116.8200.4501.57037.5004.360STOPS124.730Variable(D1) 3.6207S13-3.9301.2001.55056.3003.740S14-15.9400.150 4.0408S155.7301.2001.55056.3004.130S1623.030Variable(D2) 4.600Filter Infinity Infinity Image Infinity

[0114] Table 1 shows the surface number, radius of curvature, thickness of the center of each lens or distance between lens surfaces, index, nd, Abbe number (Abbe,vd), clear aperture, and focal length of the lens according to the present embodiment of the present invention. At this time, the unit of the radius of curvature and the thickness or distance may be mm. In Table 1, the thickness of the second lens (102), which is a prism lens, may refer to the thickness on the optical axis (OA). For example, the thickness of the second lens (102) may refer to the sum of the thickness from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S4) on the x-axis. Additionally, the thickness from the object side (S3) to the reflective surface (RS1) along the y-axis of the second lens (102) and the thickness from the reflective surface (RS1) to the sensor side (S4) along the x-axis of the second lens (102) may be the same. According to a variation, the thickness from the object side (S3) to the reflective surface (RS1) along the y-axis of the second lens (102) and the thickness from the reflective surface (RS1) to the sensor side (S4) along the x-axis of the second lens (102) may be different.

[0115]

[0116] 1st Mode 2nd Mode D12.6504.700D25.0703.020

[0117] Table 2 relates to the spacing (D1, D2) between lenses that varies when operating in either the first mode or the second mode in the optical system according to the present embodiment of the invention. Here, the first mode refers to the case of photographing an object located at infinity, and the second mode may refer to the case of photographing an object located at a macroscopic distance (e.g., within 300 mm). In the optical system according to the present embodiment, the distance between adjacent lens groups may change during the process of changing from the first mode to the second mode. The first lens group (LG1) and the second lens group (LG2) are fixed, and only the third lens group (LG3) may move. The first lens group (LG1) and the second lens group (LG2) may be fixed groups, and the third lens group (LG3) may be a moving group.

[0118] When operating from the first mode to the second mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may increase, and the distance (D2) between the third lens group (LG3) and the image sensor (300) may decrease. When operating from the second mode to the first mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may decrease, and the distance (D2) between the third lens group (LG3) and the image sensor (300) may increase.

[0119] The stroke length of the third lens group (LG3) can be 1.8 mm to 2.3 mm, and preferably about 2.050 mm. As the third lens group (LG3) moves, the optical performance of the optical system (1000) may change. For example, as the third lens group (LG3) moves, the field of view (FOV), EFL (f), Fno, BFL, etc. of the optical system (1000) may change.

[0120]

[0121] EFL(F)16.870EPD6.750BFL_15.070SD5.200BFL_23.020TD16.490FOV_123.200TD_LG17.870FOV_223.100TD_LG23.020f128.560TD_LG32.550f3-34.010f_LG198.050f414.070f_LG213.960f515.520f_LG3-48.550f6-11.710LG3_stroke2.050f7-9.880TTL21.560f813.620ImgH7.100ET11.020ΣCT12.690ET25.400ΣCG3.800ET30.530CA_Max9.425ET40.540CA_Min3.890ET50.480CA_Aver5.794ET60.840L_CT_max5.400ET71.420L_CT_min0.450ET80.960L_CT_aver1.624Fno2.500

[0122] Table 3 relates to the items of the mathematical formulas described above in the optical system (1000) of the present embodiment, including the effective focal length (EFL(F)(mm)) in the first mode of the optical system (1000), the distance from the sensor side of the last lens to the image sensor in the first mode (BFL_1(mm)), the distance from the sensor side of the last lens to the image sensor in the second mode (BFL_2(mm)), the angle of view (FOV_1(degree)) in the first mode, the angle of view (FOV_2(degree)) in the second mode, the focal lengths (f1~f8)(mm) of the first to eighth lenses (101~108), the edge thickness (ET1~ET8), the length of each lens group in the optical axis direction (TD_LG1, TD_LG2, TD_LG3), the focal lengths (f_LG1, f_LG2, f_LG3)(mm) of the first to third lens groups (LG1, LG2, LG3), and the entrance pupil. It relates to the size (EPD(mm)), the optical axis distance (SD(mm)) from the aperture (STOP) to the 16th surface (S16), the optical axis distance (TD(mm)) from the first lens (101) to the eighth lens (108), the brightness (Fno) of the optical system (1000), the stroke length (LG3_stroke) of the third lens group (LG3), the total optical axis distance of the optical system (1000) TTL(mm), ImgH(mm), the maximum effective diameter (CA_Max), the minimum effective diameter (CA_Min), the average effective diameter (CA_Aver), the maximum center thickness (L_CT_max), the minimum center thickness (L_CT_min), the average center thickness (L_CT_aver) among the first to eighth lenses (101~108), etc.

[0123] In the following, the center thickness of the first to eighth lenses (101 to 108) is denoted as CT1 to CT8, the edge thickness of the effective area of ​​each lens is denoted as ET1 to ET8, and the center gap between two adjacent lenses is denoted as CG1 to CG7. BFL (Back focal length) is the optical axis distance from the image sensor (300) to the center of the last lens. TTL is the optical axis distance from the center of the first surface (S1) of the first lens (101) to the top surface of the image sensor (300). In the following, the description of the relationship between the second lens (102), which is a prism lens, is partially omitted.

[0124] When comparing the absolute values ​​of the radius of curvature of each lens, the radius of curvature of the fifth surface (S5) of the third lens (103) at the optical axis (OA) may be the maximum among the lenses, and the radius of curvature of the thirteenth surface (S13) of the seventh lens (107) may be the minimum among the lenses. The absolute value of the radius of curvature of the first surface (S1) of the first lens (101) may be smaller than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (103) may be larger than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (104) may be smaller than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (105) may be smaller than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (106) may be larger than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (107) may be smaller than the absolute value of the radius of curvature of the fourteenth surface (S14). The absolute value of the radius of curvature of the fifteenth surface (S15) of the eighth lens (108) may be smaller than the absolute value of the radius of curvature of the sixteenth surface (S16).

[0125] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0126] Condition 1: 0.5 < |L4R1 / L4R2| < 1

[0127] Condition 2: 0.5 < |L5R1 / L5R2| < 1

[0128] Condition 3: 3.5 < |L6R1 / L6R2| < 4

[0129] Condition 4: 0.1 < |L7R1 / L7R2| < 0.5

[0130] Condition 5: 0.1 < |L8R1 / L8R2| < 0.5

[0131]

[0132] When describing the center thickness of the lenses based on the optical axis, the center thickness (CT1) of the first lens (101) is the maximum among the lenses, and the center thickness (CT3) of the third lens (103) is the minimum among the lenses. The difference between the maximum center thickness and the minimum center thickness among the lenses may be in the range of 1.0 mm or more and 1.5 mm or less.

[0133] The center thickness of each lens can satisfy any one of the following conditions.

[0134] Condition 1: CT1 > CT3, CT4, CT5, CT6, CT7, CT8

[0135] Condition 2: CT1, CT4, CT5, CT6, CT7, CT8 > CT3

[0136] Condition 3: CT1 > CT4 > CT3, CT5, CT6, CT7, CT8

[0137] Condition 4: CT1, CT4, CT7, CT8 > CT5 > CT3, CT6

[0138] Condition 5: CT1, CT4, CT5, CT7, CT8 > CT6 > CT3

[0139] Condition 6: CT1, CT4 > CT7 = CT8 > CT3, CT5, CT6

[0140]

[0141] When zooming, the gap (CG1) between the first lens (101) and the second lens (102), the gap (CG2) between the second lens (102) and the third lens (103), the gap (CG3) between the third lens (103) and the fourth lens (104), the gap (CG4) between the fourth lens (104) and the fifth lens (105), the gap (CG5) between the fifth lens (105) and the sixth lens (106), and the gap (CG7) between the seventh lens (107) and the eighth lens (108) do not change, and the gap (CG6) between the sixth lens (106) and the seventh lens (107) may change. Among the center gaps between the lenses that do not change, the gap (CG3) between the third lens (103) and the fourth lens (104) is maximum, and the gap (CG5) between the fifth lens (105) and the sixth lens (106) may be minimum. The difference between the maximum center gap and the minimum center gap among the spaced-out lens gaps may be 0.2 mm or more, for example, in the range of 0.2 mm to 0.3 mm.

[0142] The center spacing between each lens can satisfy the following conditions.

[0143] Condition 1: CG3 > CG4, CG5, CG7

[0144] Condition 2: CG3 > CG4 = CG7 > CG5

[0145] Condition 3: CG3, CG4, CG7 > CG5

[0146]

[0147] Regarding the effective aperture, the lens having the maximum effective aperture may be the first lens (101). Here, the effective aperture is the average of the effective aperture on the object side and the effective aperture on the sensor side of each lens. The lens surface having the maximum effective aperture may be the first surface (S1) of the first lens (101). The lens having the minimum effective aperture may be the seventh lens (107). The lens surface having the minimum effective aperture may be the twelfth surface (S12) of the sixth lens (106). The effective apertures of the first to eighth lenses (101-108) may be larger than the diagonal length of the image sensor (300).

[0148] The effective diameter of each lens can satisfy any one of the following conditions.

[0149] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0150] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0151] Condition 3: CA_L1, CA_L2 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0152] Condition 4: CA_L1, CA_L2, CA_L3 > CA_L4 > CA_L5, CA_L6, CA_L7, CA_L8

[0153] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4 > CA_L5 > CA_L6, CA_L7, CA_L8

[0154] Condition 6: CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L8 > CA_L6 > CA_L7

[0155] Condition 7: CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L8 > CA_L7

[0156] Condition 8: CA_L1, CA_L2, CA_L3, CA_L4, CA_L5 > CA_L8 > CA_L6, CA_L7

[0157]

[0158] Regarding the refractive index, the refractive index of the third lens (103) is the maximum among the lenses and may be greater than 1.8, for example, greater than 1.9. The fourth lens (104), the fifth lens (105), the seventh lens (107), and the eighth lens (108) may have the minimum refractive index among the lenses. For example, the refractive index of the third lens (103) may be the minimum among the lenses and may be less than 1.6, for example, less than 1.58. The difference between the maximum refractive index and the minimum refractive index may be 0.3 or greater.

[0159] The refractive index of each lens can satisfy any one of the following conditions.

[0160] Condition 1: n2, n3, n6 > n1 > n4, n5, n7, n8

[0161] Condition 2: n3 > n2 > n1, n4, n5, n6, n7, n8

[0162] Condition 3: n3 > n1, n2, n4, n5, n6, n7, n8

[0163] Condition 4: n1, n2, n3, n6 > n4 = n5 = n7 = n8

[0164] Condition 5: n2, n3 > n6 > n1, n4, n5, n7, n8

[0165]

[0166] When comparing the Abbe numbers, the Abbe number of the first lens (101) is the maximum among the lenses and may be 70 or higher. The Abbe number of the third lens (103) is the minimum among the lenses and may be 25 or lower. The difference between the maximum refractive index and the minimum Abbe number may be 70 or higher.

[0167] The Abbe number of each lens can satisfy any one of the following conditions.

[0168] Condition 1: v1 > v2, v3, v4, v5, v6, v7, v8

[0169] Condition 2: v1, v4, v5, v6, v7, v8 > v2 > v3

[0170] Condition 3: v1, v2, v4, v5, v6, v7, v8 > v3

[0171] Condition 4: v1 > v4 = v5 = v7 = v8 > v2, v3, v6

[0172] Condition 5: v1, v4, v5, v7, v8 > v6 > v2, v3

[0173]

[0174] The focal lengths (F1, F4, F5, F8) of the 1st, 4th, 5th, and 8th lenses (101, 104, 105, 108) may have a positive (+) sign. The 1st, 4th, 5th, and 8th lenses (101, 104, 105, 108) may have a positive (+) refractive power. The focal lengths (F3, F6, F7) of the 3rd, 6th, and 7th lenses (103, 106, 107) may have a negative (-) sign. The 3rd, 6th, and 7th lenses (103, 106, 107) may have a negative (-) refractive power.

[0175] When comparing the absolute values ​​of the focal lengths, the focal length of the third lens (103) is the maximum among the lenses and may be 30 or more and 50 or less. The focal length of the seventh lens (107) is the minimum among the lenses, and the absolute value of the focal length of the seventh lens (107) may be 5 or more and 10 or less.

[0176] The absolute value of the focal length of each lens can satisfy any one of the following conditions.

[0177] Condition 1: |f3| > |f1| > |f4|, |f5|, |f6|, |f7|, |f8|

[0178] Condition 2: |f3| > |f1|, |f4|, |f5|, |f6|, |f7|, |f8|

[0179] Condition 3: |f1|, |f3|, |f5| > |f4| > |f6|, |f7|, |f8|

[0180] Condition 4: |f1|, |f3| > |f5| > |f4|, |f6|, |f7|, |f8|

[0181] Condition 5: |f1|, |f3|, |f4|, |f5|, |f8| > |f6| > |f7|

[0182] Condition 6: |f1|, |f3|, |f4|, |f5|, |f6|, |f8| > |f7|

[0183] Condition 7: |f1|, |f3|, |f4|, |f5| > |f8| > |f6|, |f7|

[0184]

[0185] The combined focal length (f_LG1) of the first lens group (LG1) can have a positive (+) sign. The first lens group (LG1) can have a positive (+) combined refractive power. The combined focal length (f_LG2) of the second lens group (LG2) can have a positive (+) sign. The second lens group (LG2) can have a positive (+) combined refractive power. The third lens group (LG3) can have a negative (-) combined refractive power. Through this, light incident from the object side can move away from the optical axis direction and then converge back towards the optical axis direction, thereby forming a stable optical path.

[0186] When comparing the combined focal lengths of the first to third lens groups (LG1, LG2, LG3) in absolute terms, the combined focal length of the first lens group (LG1) may be the largest, and the combined focal length of the second lens group (LG2) may be the smallest. The relationship between the combined focal lengths of the first to second lens groups (LG1, LG2, LG3) may satisfy |f_LG1| > |f_LG3| > |f_LG2|.

[0187]

[0188] The thickness (CT1) of the first lens (101) may have a difference between the maximum and minimum thickness of at least 1 time, for example, in the range of 1.5 times to 2 times, and the center thickness (CT1) may be maximum and the edge thickness (ET1) may be minimum. The thickness (T3) of the third lens (103) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T6) of the sixth lens (106) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T8) of the eighth lens (108) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness.

[0189]

[0190] The thickness of each lens can satisfy any one of the following conditions.

[0191] Condition 1: 1.5 < CT1 / ET1 < 2, 0.5 < ET1 / CT1 < 1

[0192] Condition 2: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0193] Condition 3: 2 < CT4 / ET4 < 2.5, 0.1 < ET4 / CT4 < 0.5

[0194] Condition 4: 2 < CT5 / ET5 < 2.5, 0.1 < ET5 / CT5 < 0.5

[0195] Condition 5: 0.5 < CT6 / ET6 < 1, 1.5 < ET6 / CT6 < 2

[0196] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0197] Condition 7: 1 < CT8 / ET8 < 1.5, 0.5 < ET8 / CT8 < 1

[0198] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0199]

[0200] Among the gaps between lenses (G1-G7) having gaps between adjacent lenses, the gap (LG3) between the third and fourth lenses (103, 104) may have a minimum center and a maximum edge. The gap (G4) between the fourth and fifth lenses (104, 105) may have a maximum edge and a minimum center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a minimum center and a maximum edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may have a maximum center and a minimum edge. The seventh gap (G7) between the seventh and eighth lenses (107, 108) may have a minimum center and a maximum edge.

[0201]

[0202] FIG. 4 is a graph showing the aberration characteristics of an optical system according to the present embodiment. For example, FIG. 4 may be a graph showing the aberration characteristics in the first mode of the optical system according to the present embodiment. The aberration graph of FIG. 4 is a graph showing the measurement of longitudinal spherical aberration, astigmatic field curves, and distortion from left to right. In FIG. 4, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. Additionally, the graph for longitudinal spherical aberration is for light in the wavelength bands of approximately 470 nm, approximately 510 nm, approximately 555 nm, approximately 610 nm, and approximately 650 nm, and the graphs for astigmatic field curves and distortion are for light in the wavelength band of approximately 546 nm. In the aberration diagram of FIG. 4, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function is. In the optical system (1000) according to the present embodiment, it can be seen that the measured values ​​are adjacent to the Y-axis in almost all areas. That is, the optical system (1000) according to the present embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0203]

[0204] The optical system (1000) according to the present embodiment disclosed above may satisfy at least one or two of the mathematical formulas described below. Accordingly, the optical system (1000) according to the present embodiment may have improved optical characteristics. For example, if the optical system (1000) satisfies at least one mathematical formula, the optical system (1000) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and may have good optical performance not only at the center of the field of view (FOV) but also at the periphery. In addition, the optical system (1000) may have improved resolution. Furthermore, regarding the meaning of the thickness of the lens at the optical axis (OA) and the spacing of adjacent lenses at the optical axis (OA) described in the mathematical formulas, one may refer to the present embodiment disclosed above.

[0205]

[0206] [Mathematical Formula 1]

[0207] 1 < TD_LG2 / TD_LG3 < 2

[0208] Equation 1 can establish the relationship between the length of the second lens group (LG2) (TD_LG2) and the length of the third lens group (LG3) (TD_LG3) in the direction of the optical axis. Equation 1 is a condition for reducing aberrations and improving optical performance.

[0209] The second lens group (LG2) and the third lens group (LG3) satisfying Equation 1 can appropriately correct astigmatism aberration and coma aberration. In addition, the overall length of the zoom optical system having an appropriate zoom magnification can be reduced. In this embodiment, Equation 1 can preferably satisfy 1 < TD_LG2 / TD_LG3 < 1.5.

[0210]

[0211] [Mathematical Formula 2]

[0212] 15 < EFL(F) < 17

[0213] In Equation 2, EFL(F) is the total focal length of the optical system (1000) in the first mode. Equation 2 is a condition for limiting zoom optical performance. If the upper limit of Equation 2 is exceeded, it is difficult to secure optical performance due to chromatic aberration, and the amount of movement of each lens group increases significantly during zooming, making mechanical miniaturization difficult. If it is below the lower limit of Equation 2, there is a problem that the sensitivity of the entire optical system increases. A zoom optical system satisfying Equation 2 can secure substantially useful optical performance. In this embodiment, Equation 2 can preferably satisfy 16 < EFL(F) < 17.

[0214]

[0215] [Mathematical Formula 3]

[0216] 5 < BFL_1 < 7

[0217] In Equation 3, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens in the first mode. If Equation 3 is satisfied, installation space for the filter (400) and cover glass can be secured, and the assembly of components and coupling reliability can be improved through the gap between the image sensor (300) and the last lens. In this embodiment, Equation 3 preferably satisfies 5 < BFL_1 < 5.5. If BFL is less than the range of Equation 3, some light proceeding to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. If BFL exceeds the range of Equation 3, stray light may be introduced, and the aberration characteristics of the optical system may be degraded.

[0218]

[0219] [Mathematical Formula 4]

[0220] 40 < Ave_ABV < 50

[0221] In Equation 4, Ave_ABV is the average of the Abbe numbers of the lenses included in the optical system (1000). When Equation 4 is satisfied, optical performance can be improved by appropriately setting the factors affecting chromatic aberration. In this embodiment, Equation 4 can preferably satisfy 45 < Ave_ABV < 50.

[0222]

[0223] [Mathematical Formula 5]

[0224] 1.5 < Ave_Ind < 1.7

[0225] In Equation 5, Ave_Ind is the average of the refractive indices of the lenses included in the optical system (1000). If Equation 5 is satisfied, the optical performance can be improved by appropriately setting the factors affecting chromatic aberration. In this embodiment, Equation 4 can preferably satisfy 1.6 < Ave_Ind < 1.65.

[0226]

[0227] [Mathematical Formula 6]

[0228] 0.1 < |f_LG2 / f_LG3| < 0.5

[0229] Equation 6 can establish the relationship between the focal length (f_LG2) of the second lens group (LG2) and the focal length (f_LG3) of the third lens group (LG3). Equation 6 is a condition for reducing aberrations and improving optical performance. The second lens group (LG2) and the third lens group (LG3) satisfying Equation 6 can appropriately correct astigmatism aberration and coma aberration. In this embodiment, Equation 6 can preferably satisfy 0.2 < |f_LG2 / f_LG3| < 0.3.

[0230]

[0231] [Mathematical Formula 7]

[0232] 40 < |f_LG3| < 50

[0233] In Equation 7, f_LG3 is the focal length of the third lens group (LG3). Equation 7 is a condition for reducing aberrations and improving optical performance. In this embodiment, Equation 7 can preferably satisfy 45 < |f_LG3| < 49.

[0234]

[0235] [Mathematical Formula 8]

[0236] 1 < LG3_stroke < 5

[0237] Equation 8 can set the range of the stroke length (LG3_stroke) of the third lens group (LG3). If the upper limit of Equation 8 is exceeded, the stroke length of the third lens group (LG3) increases during focusing, making it difficult to miniaturize the optical system. If the lower limit of Equation 8 is not met, the focusing performance of the optical system may be degraded. In this embodiment, Equation 8 can preferably satisfy 2 < LG3_stroke < 3.

[0238]

[0239] [Mathematical Formula 9]

[0240] 20 < F1 < 50

[0241] In Equation 9, F1 is the focal length of the first lens (101). When Equation 9 is satisfied, the optical system (1000) can have a set angle of view and an appropriate focal length, and can set the angle of view to be large within an appropriate TTL range. If it is below the lower limit of Equation 9, the effective aperture or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes large. If it exceeds the upper limit of Equation 9, the influence of the first lens (101) in the entire optical system decreases, and it is necessary to increase the refractive power of the lenses, which makes it difficult to correct spherical aberration or distortion aberration. In this embodiment, Equation 9 can preferably satisfy 25 < F1 < 30.

[0242]

[0243] [Mathematical Formula 10]

[0244] 1 < CT1 < 2

[0245] In Equation 10, CT1 is the center thickness of the first lens (101). If Equation 10 is satisfied, the thickness of the first direction (y-axis direction) of the optical system (1000) can be prevented from increasing, and a miniaturized optical system can be realized. In this embodiment, Equation 10 can preferably satisfy 1.5 < CT1 < 1.8.

[0246]

[0247] [Mathematical Formula 11]

[0248] 10 < TTL < 30

[0249] In Equation 11, TTL (Total track length) refers to the distance (mm) along the optical axis (OA) from the center of the first surface (S1) of the first lens (101) to the top surface of the image sensor (300). In this embodiment, Equation 11 can preferably satisfy 20 < TTL < 25.

[0250]

[0251] [Mathematical Formula 12]

[0252] 6 < ImgH < 8

[0253] In Equation 12, ImgH represents the maximum diagonal length of the image sensor (300). Equation 12 can set the diagonal size (ImgH) of the image sensor (300) and can provide an optical system having a large mobile image sensor size. In this embodiment, Equation 12 preferably satisfies 7 < ImgH < 7.5.

[0254]

[0255] [Mathematical Formula 13]

[0256] 2 < Fno < 3

[0257] Equation 13 can set the range of Fno of the optical system (1000). If Equation 13 is satisfied, an image of suitable brightness can be provided, and a large amount of light can be received by the image sensor. In this embodiment, Equation 13 can preferably satisfy 2.3 < Fno_wide < 2.7.

[0258]

[0259] [Mathematical Formula 14]

[0260] 20 < FOV_1 < 30

[0261] In mathematical formula 14, the range of the field of view (FOV_1) in the first mode can be set. In mathematical formula 14, a field of view suitable for a mobile optical system can be provided. In this embodiment, the FOV can preferably satisfy 22 < FOV_1 < 25.

[0262]

[0263] [Mathematical Formula 15]

[0264] 2 < TTL / CA_max < 5

[0265] In Equation 15, CA_max represents the largest effective diameter (mm) among the object side and sensor side of the plurality of lenses, and TTL (Total track length) represents the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101) to the top surface of the image sensor (300). Equation 15 establishes a relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved mobile optical system. In this embodiment, Equation 15 preferably satisfies 2.2 < TTL / CA_max < 2.5.

[0266]

[0267] [Mathematical Formula 16]

[0268] 2 < TTL / ImgH < 5

[0269] In Equation 16, TTL (Total track length) refers to the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the top surface of the image sensor (300), and ImgH refers to the maximum diagonal length of the image sensor (300). When Equation 16 is satisfied, the optical system (1000) can have a TTL for application to the mobile image sensor (300), thereby providing improved image quality. If it is below the lower limit of Equation 2, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration; if it exceeds the upper limit of Equation 2, the effective aperture or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes larger. In this embodiment, Equation 16 preferably satisfies 3 < TTL / ImgH < 3.5.

[0270]

[0271] [Mathematical Formula 17]

[0272] 2 < EFL(F) / ImgH < 4

[0273] In Equation 17, EFL(F) is the total effective focal length of the optical system (1000) in the first mode, and ImgH represents the maximum diagonal length of the image sensor (300). If Equation 17 is satisfied, the mobile image sensor (300) may have improved aberration characteristics in terms of size. In this embodiment, Equation 17 preferably satisfies 2.2 < EFL(F) / ImgH < 2.5.

[0274]

[0275] [Mathematical Formula 18]

[0276] 0.1 < ΣCT / TTL < 1

[0277] Equation 18 can establish a relationship between the sum of the center thicknesses of the lenses (ΣCT) and the distance (TTL) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (300) along the optical axis (OA). If the upper limit of Equation 18 is exceeded, the number of lenses increases, and the movement of the moving lens group in the optical system may become disadvantageous. If the lower limit of Equation 18 is not met, the focusing performance of the optical system may be degraded. In this embodiment, Equation 18 preferably satisfies 0.5 < ΣCT / TTL < 0.8.

[0278]

[0279] [Mathematical Formula 19]

[0280] 0.1 < ΣCG / TTL < 1

[0281] Equation 19 can establish a relationship between the sum of the gaps between adjacent lenses (ΣCG) and the distance (TTL) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (300) along the optical axis (OA). If the upper limit of Equation 19 is exceeded, the moving distance of the moving lens group in the lens optical system increases, and consequently, the current consumed during the focusing operation may increase. If the lower limit of Equation 19 is not met, the focusing performance of the optical system may be degraded. In this embodiment, Equation 19 preferably satisfies 0.1 < ΣCG / TTL < 0.2.

[0282]

[0283] [Mathematical Formula 20]

[0284] 2 < ΣCT / ΣCG < 5

[0285] Equation 20 can establish a relationship between the sum of the center thicknesses of the lenses (ΣCT) and the sum of the spacing between adjacent lenses (ΣCT). If the upper limit of Equation 20 is exceeded, the number of lenses increases, and the movement of the moving lens group in the optical system may become disadvantageous. If the lower limit of Equation 20 is not met, focusing performance may be degraded. In this embodiment, Equation 20 preferably satisfies 3 < ΣCT / ΣCG < 4.

[0286]

[0287] [Mathematical Formula 21]

[0288] 1 < CA_max / CA_min < 3

[0289] In Equation 21, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and CA_min represents the minimum effective diameter among the object sides and sensor sides of the lenses. When Equation 21 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In this embodiment, Equation 21 preferably satisfies 2 < CA_max / CA_min < 2.5.

[0290]

[0291] [Mathematical Formula 22]

[0292] 1 < CA_max / ImgH < 5

[0293] In Equation 22, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and ImgH represents the maximum diagonal length of the image sensor (300). When Equation 22 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In this embodiment, Equation 22 preferably satisfies 1 < CA_max / ImgH < 1.5.

[0294]

[0295] [Mathematical Formula 23]

[0296] 0.1 < CA_min / ImgH < 1

[0297] In Equation 23, CA_min represents the minimum effective diameter among the object sides and sensor sides of the lenses, and ImgH represents the maximum diagonal length of the image sensor (300). When Equation 23 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In this embodiment, Equation 23 preferably satisfies 0.5 < CA_min / ImgH < 0.8.

[0298]

[0299] [Mathematical Formula 24]

[0300] 0.35 < |L1R1| / |L3R2| < 1

[0301] In Equation 24, L1R1 is the radius of curvature of the object side of the first lens (101), and L3R2 is the radius of curvature of the sensor side of the third lens (103). Equation 24 is a condition for OIS correction by tilting the prism lens; if it is below the lower limit, there is a problem of significant reduction in resolution when correcting OIS through prism lens tilting, and if it exceeds the upper limit, there is a problem of Fno becoming larger. In this embodiment, Equation 24 can preferably satisfy 0.4 < |L1R1| / |L3R2| < 0.6.

[0302]

[0303] [Mathematical Formula 25]

[0304] 1.5 < n4 < 1.6

[0305] In Equation 25, n4 is the refractive index of the fourth lens (104) at 587.6 nm in the d-line. If Equation 25 is satisfied, the optical system can maintain good optical performance with improved aberrations and can set a size for a slim and compact structure. In this embodiment, Equation 25 can preferably satisfy 1.53 < n4 < 1.58.

[0306]

[0307] [Mathematical Formula 26]

[0308] 50 < v4 ​​< 60

[0309] In Equation 26, v4 is the Abbe number at the d-line of the fourth lens (104) at 587.6 nm. If Equation 26 is satisfied, the optical system can maintain good optical performance with improved aberrations and can set a size for a slim and compact structure. In this embodiment, Equation 26 can preferably satisfy 55 < v4 ​​< 60.

[0310]

[0311] [Mathematical Formula 27]

[0312] 15 < v6 < 45

[0313] In Equation 27, v6 is the Abbe number at 587.6 nm of the d-line of the sixth lens (106). If Equation 27 is satisfied, the optical system can maintain good optical performance with improved aberration and can set a size for a slim and compact structure. In this embodiment, Equation 27 can preferably satisfy 30 < v6 < 40.

[0314]

[0315] [Mathematical Formula 28]

[0316]

[0317] In Equation 28, Z represents Sag, which can mean the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Y represents the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. Additionally, A, B, C, D, E, and F can represent the aspheric constants.

[0318]

[0319] The optical system (1000) according to the present embodiment may satisfy at least one or two of the mathematical formulas 1 to 28. In this case, the optical system (1000) may have improved optical characteristics. Specifically, when the optical system (1000) satisfies at least one or two of the mathematical formulas 1 to 28, the optical system (1000) may have improved resolution and may improve aberration and distortion characteristics. In addition, the optical system (1000) may secure a Back Focal Length (BFL) for applying an image sensor (280), compensate for the degradation of optical characteristics due to temperature changes, and minimize the gap between the last lens and the image sensor (280), thereby having good optical performance in the center and periphery of the field of view (FOV).

[0320]

[0321] Mathematical Formula Example 11 < TD_LG2 / TD_LG3 < 21.184215 < EFL(F) < 1716.87035 < BFL_1 < 75.070440 < Ave_ABV < 5047.451.5 < Ave_Ind < 1.71.63960.1 < |f_LG2 / f_LG3| < 0.50.288740 < |f_LG3| < 5048.55081 < LG3_stroke < 52.050920 < F1 < 5028.560101 < CT1 < 21.7701110 < TTL < 3021.560126 < ImgH < 87.100132 < Fno < 32.5001420 < FOV_1 < 3023.200152 < TTL / CA_max < 52.288162 < TTL / ImgH < 53.037172 < EFL(F) / ImgH < 42.376180.1 < ΣCT / TTL < 10.603190.1 < ΣCG / TTL < 10.162202 < ΣCT / ΣCG < 53.711211 < CA_max / CA_min < 32.423221 < CA_max / ImgH < 51.327230.1 < CA_min / ImgH < 10.548240.35 < |L1R1| / |L3R2| < 10.5251.5 < n4 < 1.61.552650 < v4 ​​< 6056.32715 < v6 < 4537.5

[0322] Table 4 shows the result values ​​for the above-described mathematical formulas 1 to 27 in the optical system (1000) of the embodiment. Referring to Table 4, it can be seen that the optical system (1000) satisfies at least one, two or more, or three or more of mathematical formulas 1 to 27. Specifically, it can be seen that the optical system (1000) according to the embodiment satisfies all of mathematical formulas 1 to 27. Accordingly, the optical system (1000) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0323] FIG. 6 is an example of a portable terminal having an optical system according to the present embodiment. As shown in FIG. 6, the portable terminal (1500) may include a camera module (1520), a flash module (1530), and an autofocus device (1510) provided on one side or the rear side. Here, the autofocus device (1510) may include a surface-emitting laser element and a light receiver disclosed above as a light-emitting layer.

[0324] The flash module (1530) may include an emitter that emits light inside it. The flash module (1530) may be operated by the camera operation of the mobile terminal or by the control of the user. The camera module (1520) may include an image capturing function and an autofocus function. For example, the camera module (1520) may include an autofocus function using an image.

[0325] The autofocus device (1510) may include an autofocus function using a laser. The autofocus device (1510) may be primarily used under conditions where the autofocus function using the image of the camera module (1520) is degraded. Additionally, although not shown in the drawing, at least one additional camera module may be disposed on the front of the mobile terminal (1500). At least one of the camera modules within the mobile terminal may have the tele-type folded optical system disclosed above.

[0326] An optical system or camera module according to an embodiment of the invention, and a lens assembly according to various embodiments, may be applied to an electronic device employing an image sensor, for example. A lens assembly according to an exemplary embodiment may be applied to various electronic devices such as digital cameras, interchangeable lens cameras, video cameras, mobile phone cameras, cameras for small mobile devices, VR, AR, drones, or manned / unmanned aircraft.

[0327] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0328] Furthermore, although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. Includes first to third lens groups arranged along the optical axis, and The above first lens group has a positive (+) refractive power, and The above second lens group has a positive (+) refractive power, and The above third lens group has negative (-) refractive power, and The above first lens group includes a prism lens, and The first lens group and the second lens group are fixed groups, and The above third lens group is an optical system that is a moving group.

2. In Paragraph 1, The first lens group above is an optical system comprising a single power prism lens having a convex side on the object and a concave side on the sensor.

3. In Paragraph 1, The above first lens group includes a first lens, a second lens which is a prism lens, and a third lens, and The first to third lenses mentioned above are bonded lenses, and The above second lens group includes a fourth lens, a fifth lens, and a sixth lens, and The above third lens group is an optical system including a seventh lens and an eighth lens.

4. In Paragraph 3, The first lens above has a positive (+) refractive power, and The above third lens is an optical system having negative (-) refractive power.

5. In Paragraph 3, The above-mentioned fourth lens has a positive (+) refractive power, and The above-mentioned fifth lens has a positive (+) refractive power, and The above-mentioned sixth lens is an optical system having negative (-) refractive power.

6. In Paragraph 3, The above seventh lens has a negative (-) refractive power, and The above eighth lens is an optical system having positive (+) refractive power.

7. In Paragraph 3, The above-mentioned fourth lens and fifth lens are an optical system having a meniscus shape with a convex side surface.

8. In Paragraph 3, The above-mentioned sixth lens has a meniscus shape with a convex side surface, and The above seventh lens is an optical system having a meniscus shape with a concave side surface of the object.

9. In Paragraph 3, An optical system in which an aperture is positioned between the sixth lens and the seventh lens.

10. In Paragraph 1, An optical system satisfying the following condition. <Condition> 1 < TD_LG2 / TD_LG3 < 2 (In the above conditional equation, TD_LG2 is the length of the second lens group in the optical axis direction, and TD_LG3 is the length of the third lens group in the optical axis direction.)

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